DIY LED Hood: Prebuild Thoughts...

Lampshade · #1 01-26-2011, 10:10 PM

Quote:

on this topic, have you seen any dimming programs for Arduino using a varable voltage output instead of PWMs?

Arduino's can't output a variable voltage, but you can buy filters that will change PWM outputs to a 0-5v or 0-10V. check out:http://www.nano-reef.com/forums/inde...owtopic=230743 - different values work for different pulse widths, there's online calculators to see what you need.

As for heatsinks you are right, overbuilt is no problem at all with me either. I'm not going to go buy 60" of 10" pure aluminum heat sink with 1.5": fins now though, after calculating it a bare piece of aluminum with a fan on it would work "in theory". I'm going to probably run aluminum channel, and also I'm going to have an arduino running my LED's, so for $2.50 i can get a thermometer on the heatsink to shutoff for overheating, i'll proably put 4-5 of them on just to be sure.

Lampshade · #2 01-26-2011, 10:24 PM

Quote:

Now do you know how I would calculate the AC power requirements?

Your AC should be pretty much Watts in = Watts out/efficiency

Drivers vary efficiency depending on how well they're used(they like to be run near max all the time). usually >70% though. so 48LED's, driven at 3v per LED, at 750mA(3/4 load) would be about 86.4W at 80%, so 0.72A at 120V. Not bad at all...

GMGQ · #3 01-26-2011, 10:28 PM

How did you calculate that?

And what is that in terms of a power supply's AC_out and Amps? So in your example, would this one suffice?
http://ledsupply.com/04004-p96.php

Quote:

Originally Posted by Lampshade

Your AC should be pretty much Watts in = Watts out/efficiency

Drivers vary efficiency depending on how well they're used(they like to be run near max all the time). usually >70% though. so 48LED's, driven at 3v per LED, at 750mA(3/4 load) would be about 86.4W at 80%, so 0.72A at 120V. Not bad at all...

Lampshade · #4 01-26-2011, 11:46 PM

Watts is just P = EI, or watts = voltage * current

GMGQ · #5 02-18-2011, 06:33 PM

For guys that have DIY LED setups, do you just run the royal blue array at the lowest voltage for moonlights? Or would that be overkill (i.e. if you had say 24/48 in blue LEDs)?

Or did you install a separate set of blues for moonlights? And if so, how many do you run? My tank is 48" wide, will 5-6 LEDs evenly spaced be sufficient?

GMGQ · #6 02-18-2011, 06:48 PM

Just an update on my mini LED build. I'm going down to point roberts on saturday to pick up a bunch of stuff that I ordered:

- Weller 40W Soldering Station (figure it's time to upgrade from my old 25W Radio Shack soldering iron)
- 7"x6" heatsink from HeatsinkUSA.com
- Meanwell LPC-35-700W driver from RapidLED.com

And I already have the LEDs from Milad (4 x XP-E CW, 4 x XP-G RB).

I'm going to pick up some Artic Silver Thermal Adhesive from NCIX (I get a discount there), and I should have enough misc electrical supplies in my toolbox. Oh I want to get some ballast quick disconnects from Home Depot.

I should also pick up a sheet of Acrylic from IP&P to make a splash guard.

TheMikey · #7 02-18-2011, 08:01 PM

I can't find the thread, but when I was considering doing a DIY, I came across a thread on RC about LED optics.

The poster looked at the PAR range between 40, 60, and 80 degree (I think) optics and found that the 60 degree optics were the most efficient and gave the best PAR.

I'll dig around a bit longer and see if I can find it...